Patent US1371448A successfully refreshed from Google Patents.
Patent US4955267A successfully refreshed from Google Patents.
US4955267A
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Method of making a PTC conductive polymer electrical device
Assignee: Tyco International Ltd Bermuda
•
Filing: 1988-01-21
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Granted: 1990-09-11
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Expires: 2008-01-21
Abstract
Abstract Conductive polymer PTC compositions have improved properties, especially at voltages of 200 volts or more, if they are very highly cross-linked by means of irradiation, for example to a dosage of at least 50 Mrads, preferably at least 80 Mrads, e.g. 120 to 600 Mrads. The cross-linked compositions are particularly useful in circuit protection devices and layered heaters.
Inventors
- 👤 Stephen M. Jacobs
- 👤 Mary S. McTavish
- 👤 Frank A. Doljack
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:32
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/02; H01C7/027; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49083
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
65 words
A process for the preparation of an electrical device which comprises (1) melt-extruding a radiation cross-linkable PTC conductive polymer composition to form a laminar PTC element which does not contain an electrode; (2) cross-linking the conductive polymer by irradiating substantially the whole of the PTC element to a dosage of at least 50 Mrads; and (3) securing metal foil electrodes to the irradiated PTC element.
Claim 2
Dependent Claim
65 words
A process for the preparation of an electrical device which comprises (1) melt-extruding a radiation cross-linkable PTC conductive polymer composition to form a laminar PTC element which does not contain an electrode; (2) cross-linking the conductive polymer by irradiating substantially the whole of the PTC element to a dosage of at least 50 Mrads; and (3) securing metal foil electrodes to the irradiated PTC element.
Claim 3
Dependent Claim
14 words
A process according to claim 1 wherein the dosage is at least 60 Mrads.
Claim 4
Dependent Claim
14 words
A process according to claim 2 wherein the dosage is at least 80 Mrads.
Claim 5
Dependent Claim
14 words
A process according to claim 1 wherein step (2) is conducted before step (3).
Claim 6
Dependent Claim
14 words
A process according to claim 1 wherein step (2) is conducted after step (3).
Claim 7
Dependent Claim
80 words
A process for the preparation of an electrical device which comprises (1) forming a laminar PTC element of a radiation cross-linkable conductive polymer composition; (2) securing electrodes to the laminar PTC element, the electrodes being displaced from each other so that at least a substantial component of current flow between the electrodes is along one of the large dimensions of the element; and (3) irradiating substantially the whole of the PTC element to a dosage of at least 50 Mrads.
Claim 8
Dependent Claim
80 words
A process for the preparation of an electrical device which comprises (1) forming a laminar PTC element of a radiation cross-linkable conductive polymer composition; (2) securing electrodes to the laminar PTC element, the electrodes being displaced from each other so that at least a substantial component of current flow between the electrodes is along one of the large dimensions of the element; and (3) irradiating substantially the whole of the PTC element to a dosage of at least 50 Mrads.
Claim 9
Dependent Claim
15 words
A process according to claim 6 wherein step (2) is carried out before step (3).
Claim 10
Dependent Claim
15 words
A process according to claim 6 wherein step (2) is carried out after step (3).
Claim 11
Dependent Claim
14 words
A process according to claim 6 wherein the dosage is at least 80 Mrads.
Claim 12
Dependent Claim
20 words
A process according to claim 1 wherein the PTC conductive polymer comprises a polymeric component having carbon black dispersed therein.
Claim 13
Dependent Claim
19 words
A process according to claim 10 wherein the carbon black is the sole particulate conductive filler in the composition.
Claim 14
Dependent Claim
18 words
A process according to claim 10 wherein the polymeric component consists essentially of one or more crystalline polymers.
Claim 15
Dependent Claim
13 words
A process according to claim 10 wherein the polymeric component comprises a polyolefin.
Claim 16
Dependent Claim
12 words
A process according to claim 10 wherein the polymeric component comprises polyethylene.
Claim 17
Dependent Claim
14 words
A process according to claim 10 wherein the polymeric component consists essentially of polyethylene.
Claim 18
Dependent Claim
23 words
A process according to claim 10 wherein the cross-linked PTC conductive polymer has a resistivity at 23° C. of less than 50 ohm-cm.
Claim 19
Dependent Claim
18 words
A process according to claim 1 wherein the PTC element has a thickness of at least 0.040 inch.
Claim 20
Dependent Claim
18 words
A process according to claim 17 wherein the PTC element has a thickness of at least 0.060 inch.
Claim 21
Dependent Claim
18 words
A process according to claim 18 wherein the PTC element has a thickness of at least 0.100 inch.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-09-10 | 1994-03-12 | 1994-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-10 | 1998-03-12 | 1998-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-10 | 2002-03-12 | 2002-09-11 | $7700.00 | Window Closed / Lapsed |